ok so a friend of mine wants me to help him do an install for another friend, including a deck, sub, two amps and speakers in cressida he just bought, but i had a question. i was told it already has a amplifier in it, and that its tricky to get around installing anything without going through this amplifier. i did a search for harnesses and the only one i found was for ones with no amp or jbl premium system. i'm just wondering. if we change the head unit and then connect the first aftermarket amp with the speakers connected to it, then do the sub and blah blah blah, will the speakers work? or do we really have to go through the factory amp?

i figured the new head unit would allow the rcas to carry a signal to the new amp and let the speakers play, but from what i've heard from him we have to go through the amp somehow

 

Run RCAs from the aftermarket deck to the new amps. Then run new speaker wires from the aftermarket amps to the speakers there will be no need at all to even look at the factory amp as it will be completely bypassed. Sounds like you will be replacing everything so there will be no factory equipment hooked up? The factory amp will not be needed then.
HTH
Nick

 

thats what i figured, thanks Nick, i just needed the reassurance...now for me to make an "i told you so" phone call

 

I love making those calls. Glad I could help.